The effect of annealing on the microstructure of Cu-Al-Ni-Mn shape memory alloy microwires

Abstract

Shape memory alloys exhibit superelasticity and the shape memory effect by undergoing a diffusionless phase transformation between the austenite and martensite phases. Nickel-titanium alloys are currently the most common material used. However, due to their expensive cost, alternatives such as Cu-based alloys have been investigated. Cu-based alloys have exhibited the shape memory effect and have achieved 6-8% strain recovery. This work investigates Cu-Al-Ni- Mn shape memory alloys in the form of microwires with the potential application in smart textiles. Wire microstructure and composition, transition temperatures, and strain recovery were analyzed after the wires were subjected to varying annealing times and temperatures. These data were used to determine the ideal conditions to achieve the most shape memory and superelasticity.